Accelerometer



Jan. 26, 1932. H, Fl BLANCHARD 1,842,384

ACCELERQMETER Filed Feb. 17. 1931 BRAKIN'G SECONDE,

\ To ACCELRATE PH 1 :30 M.P.H. 2 FROM T025M.4 To sToP l 8 SEC-5 15 l A `FT 35 @Y 4 9 d 9 l/ '5 Z0 l h .o 1fig/45 f@ 6 zz .lllllrH Patented Jan. 26, 1932 UNITED .STA

Tas

yParri-:m oFFlcE 'Application led February 17, 1931. Serial No'. 516,356. A

The present invention relates broadly to precise instruments and more especially to an accelero'meter andv decelerometer.

, .The device comprising the present invention is adapted more especially for use with ,conveyances such as automobiles, motor boats,

airplanes or other moving vehicles. y

It is frequently desirableto determine in connection, more especially withv an yauto- 10 mobile equipment, the efficiency of the braking system and also the eiiiciency of the power unit, whereby it vmay be accurately ascertained as to the distance in which the automobile may be brought to a stop from a predetermined speed or the'time in which the automobile may be accelerated up lto a predetermined speed.

The present invention comprises broadly the utilization of indicating members arranged in series as to their effective indicating -movement under the influence of^changingj speeds.

One embodiment` of the invention` com prises a pluralit of inclined vrunways with the inclination o each runway being slightly greater than the other and on predetermined calibrated inclines, and small spheres preferably steel balls, arranged on the runways; so that with the device substantially on a level line, in an automobile, the spheres on certain of the inclined paths will move upwardly due to their inertia when the automobile is accelerated or decelerated as will hereinafter be more fully explained. The

35 spheres which start to move, assuming the rate of speed change to be constant, will continue their movement as far as the runways will permit. until the rate of speed change is stopped. By observing the spheres which have movedfrelative to those which have not moved, the rate of'deceleration or acceleration is determined as between the last sphere on" the scale which did not move and the rate ofspeed. change represented by the adjacent t5 sphere which did move.

' The invention broadly may be stated to be a construction including a mass which'does not move until the inertia of the mass due to the'rate of speed change exceeds a predetermined amount, at which time movement of the mass occurs. The amount of force required to move adjacent masses is controlled in such manner as to comprise a scale for observation.

The present invention may be embodied in different structures from those herein disclosed and it therefore is to be understood that the disclosure herewith is illustrative and not to be considered in the limiting sense.

Fig. 1 illustrates a side view of a device e0 according to the present invention constructed in portable form.

FFig. 2 is a Asectional view on line 2 -2 of Fig. 3 illustrates one formof the device as o5 an instrument adapted to bemounted on the instrument board of an automobile, airplane,

or the like. Fig. 4 is a sectional viewv on line 4-4,

Fig. 3.

FFig. 5 is a sectional view on line 5 5 of Fig. 6 illustrates a resetting slide used in the construction shown in Figs. 3, 4 and 5.

Fig. 7 diagrammatically illustrates the in- 75 vention as being carried out by the use of permanent magnets.

Referring to the drawings and-more especially to Figs. 1 and 2, which illustrate one embodiment of the device adapted for automobile use, a body member 1 is provided with a plurality of slots comprising upwardly inclined portions'2, 4, 5 6, 7, and 8 and downwardly inclined portions 9, 10, 11, 12, 14 and 15. The upwardly inclined portions 85 gradually decrease in inclination from the upper inclined portion 2 to the lowest inclined portion 8.. Each of these slots carry small spheres 16 preferably comprising small steel balls. A pair of transparent plates 1 7 and 18 of glass or other suitable material are secured on the sides of the body portion 1 by means of the frame 19 and these side members retain the spheres 16 within their respective slots. As illustrated in Fig. 1, the left ends of the slots 2 to 8 inclusive are' associated with a scale adapted for use in brake testing. The readin s on this scale are associated with the inclination of the portions of the slots 2 to 8 to a horizontal 100 line withreference to the inertia of the spheres as produced by deceleration. The

construction of the device and t-he scale provided as illustrated in Figfl is adapted to test the eiiciency of brakes of an automobile in decelerati-ng the speed of the car from thirty miles per hour to stop. With the device set on the side window sill of the car with the scale 20 for braking toward the rear end of the lcar and with the car running at thirty miles per hour, the brakes are applied and ifkthe three lower-balls move up*- the inclines 6, 7, and 8 and over into the de-l clines 12, 14 and 15, the car has been stopped at suchrate that the car speed will diminish from thirty miles per hour to Zero in a distance betweenforty-iive and fifty feet. It

all of the spheres except the top sphere move over from the left end of the slots to the right ends thereof, then the rate of decelerav Ition is equal to stopping the car from a thirty mile per hour speed'in a distance between thirtyfive and forty, feet. If all of the spheres move over. from the left end to the right endof the slots, then the car has been deceleratedfrom'thirty'miles per hour to stop within a distance of thirty-five feet or less. With this instrument, it is not 4necessary to bring the`car to a completestop because shortly after the brakes become effective, the spheres move in accordancewith I the deceleration rate and the effectiveness of the brakes may be quickly determined because if the braking is continued, the cai` eration, then thel car has accelerated from will be brought to a complete stop within the number of feet as indicated by the movement of the s heres.

If it is desired to test the acceleration of the car, the devicev is tipped edgewise to cause all of-fthe steel balls 16 to move to the .right end of the slots, where these balls willremain at rest due to the fact that the portions of the slots in which the balls are nowl ive to twenty-five miles/an hour at a rate of between fourteen and twelve seconds. If all of the balls 'except the one at the top have movedfrom .right to left, then the acceleratin from five to twenty-five miles per hour has taken place in' a time period between eight and nine seconds. If all of the balls have moved from right to left; then the acceleration from five to twenty-five miles per hour has taken place in eight seconds or less. It will be observed that the inclined portions If only thev at the left oi the middle of the grooves-'isl greaterv than the inclinations at the right of the rmiddle of the grooves. This is for the reason that deceleration usually takes place vat a more-rapid rate than acceleration and therefore steeper inclines are used to indiy cate deceleration than are used to indicate acceleration.

Figs. 3,4, 5 and 6 illustrate an equipment in accordance with the present invention adapted to comprise an instrument boarddevicefor use on automobiles or the like. In

this form of the device, a body 22 is provided' on the right side thereof, as viewed from the front in Fig. 3, with upwardly inclined -runways 24, 2.5, 26, 27, 28 and 29. Steel yballs 30 are provided in each of the said runwa s sto which are ofgraduated inclination with t e cover`34 covers the front plate 31, and'l comprises a stop to prevent the balls from escapingrfrom the ball runways. A resetting slide 35 is provided with a handle 36 and carries a stop pin 37 which operates in a slot 38 in the body 22. This resetting slide is provided with openings 39 of such size as to retain any f ball which rolls up the ball passageway. Upon raising the handle 36 to the limit allowed by the stop in 37 in the slot ,38, these \balls roll out of the resetting bar and back into position against the cover glass 34, in view of the fact that the holes 39 in the reset 40 is associated with the openings 32 and the balls 30 are normally in position to be viewed by the operator through the openings 32. As- Isuining that aftest is to be made, the brakes nslide are slghtlyinclined toward the front of the device. A braking or decelerating scale are applied and the car decelerates at such a J rate that the Ilowest ball disappears from the lower opening 32 as illustrated in Figs. 3 and 4*. This immediately informs the operator that the brakes'are operating at such rate that he can stop the car going at a thirty mile per hour, rate in a distance of seventy as other balls disappear from view during brakin test, the reading of the scale indi- Cates t brought to a stop from a thirty mile spee The right half of the instrument as illus trated in Figs. 3 and 5 is constructed to register acceleration and in this case, the ball runways 41, 42, 44, 45, 46 and 47 are inclined in the opposite direction, namely, from the back of the bod 21 toward the face of the instrument boar These runways 41 tov 47 are likewise of graduated inclination andthe reset bar 35 is now provided adjacent the face plate 31. .The faceplate is provided with openings 48 identical with the openings 32 at'the left.

These openings/48 are associated with a scale V49 whichis4 graduated to represent the rate of feet, and

e distance lin which the car ma be acceleration from ivetotwenty-live' miles in seconds. If thecar is accelerated, and the operator observes the lower ball 30 to be visi;

- ble, then the rate of acceleration has been at least equal to increasing the speed of the car from iive to twenty-five miles in fourteen seconds. If two ballsl are visible, then the rate of acceleration has been at least veto twentyive miles in twelve seconds, etc.

The invention may be embodied in other `forms, for example, the form diagrammati- Vballs and will roll to the stop pockets 58 in the middle of the runways. Since the magnets 5() to 56 are graduated in strength, the movement of the steel balls from the magnets again ybecomes an indicator of theratewt deceleration-on each ball in its respective magnet representing a point on a predetermined scale.

l The magnets 59, 60, 61, 62, 64 and 65 shown at the right of Fig. 7"-are weaker magnets than those shown at the left. When it is desired to use this instrument for acceleration, a strong magnet is applied to the steelballs to pull these balls away from the magnets at vthe left and carry the balls across so that they become attached to the magnets at-the right. The device is'now set for testing acceleration and the tests occur as previously described,

namely, that the accelerationis determined by the steel balls which are pulled away from the respective magnets and lodge in the pockets 58. Of course, a magnet is used to lift the balls from the pockets 58 and carry them tn whichever side of the instrument is to be used.

It is toy beunderstood that the inclinationY of the ball runways, where this 'type of de- I vice is used, is determined by actual test in order to calibratethe irst instrument. After av calibration has been obtained, then duplicates of the first instrumentwill be as accurate as the calibrated instrument. -The same observation yapplies to the .use of. permanent magnets. In thecase of permanent magnets,

it may be necessary after'long periods of time to recalibrate the device yin view of the -pos sible loss of magnetism from the said permanent magnets.4 In the form of device 'comprising inclined slots, however, no recalibration is necessary after the inchnatlonkof *the slots has once been determined.

Having described myv invention, I,claim:

l1. A\device of the class described comprising a body'member provided with a plurality of calibrated inclined slots, eachof said slots being of predetermined inclination' with the. inclination of one slot being different from that of the adjacent slots and spheres mounted'in saidslots and adapted to move 1n said slots in accordance with the rateAof change at which said device is moved in the l direction of the length of said slots.

2. A device of the class described comprising a body member provided with graduated inclined runways, movable means mounted insaid runways, saidrunways being progresmoved in the direction of the length of lplurality of indicators, andmeans to retain .the indicators whi h move under the influence of inertia in a d1 erent position from the indicators which do not move whereb theindicators whichmove under the influence of inertia due to change in speed to which said device is subjected determines iwith reference to said scale therate of said speedA change. 4. In a device of the class described, a plurality of movable indicators normally tending to move under the -force of inertia when said device is subjected to a change in speed, restraining means for eachof said indicators normally holding said indicators from moving until the inertia force of said indicators exceedssaid restraining means, said restraining means being graduated to- Vform a series of graduated indicators adapted to indicate speed change, and a scale associated with said indicators. c i

5. A device of the class described comprising a body member provided with a plurality of inclined-runways extending in the direction of movement to b e measured, asmovablle member in each of said runways, said runways being progressively inclined one to the other in accordance with a' predetermined scale whereby each member will only move in its particular runway when the inertia of said member due to change of speed in the direction of said runway exceeds a orcegnecessary to cause saidmefnber to move upwardly on its inclined runway. 'A

6. A device of the class described comprising a relatively iat 4body member provided lwith a plurality 'of inverted V-shaped runways, they inclination of the legs of said inverted V-shaped runways being graduated relatively to predetermined scales, spheres freelymovable in said runways, and means to retain said spheres in position in said run .p ways.

7. A device of the class described comprising a relatively flat body member provided tion of the legson the other sideof the runways being graduated relative to another l scale, sphe`res freely movable in said runways, and means to retain said spheres in position in said runways.

8. Adevice of the class described comprising a relatively flat body'inember provided with a plurality of inclined runways, spheres mounted i-n said runways, the inclination of said runways relative to thebase of said. device being graduated in accordance with va predetermined scale, transparent means covering one side of said runways whereby the position of said spheres maybe observed.

9. A device of the class described lcomprising a body portion, .al base on saidbody porftion, a plurality of inclined runways provided in said body portion one above another, spheres freely movable in said runways, said lrunways being inclined one to the other in accordance with apredetermined scale, and

prising a-face plate, 'a body portion back of` said face plate, said body portion being provided with aplurality of inclined runways,

'the inclination of said runways being graduated in accordance with a predetermined scale, spheres in each of said runways, and

means provided with openings adjacent the v -strained from moving until the momentum thereof exceeds the force necessary to `overcome the component of gravity restraining the movement thereof.

'HAROLD F. BLANCHARD.

means retaining said spheres in said runways' with said spheres at one end thereof being visible.`

10. A device ofthe class described comprising an instrument for indicati-ng change ofe speed, said instrument being. provided wit-,ha face plate, a body portion back of said face plate and having inclined runways therein, said runways being inclined relative to said face plate in accordance with a predetermined scale, a sphere in each of said runways, means fory preventing a sphere which has passed up its respective runways sfrom returning except at the will of the operator, and means for restoring such spheres to their respective runways. r 11, A device of tbe class described comprising an instrument for indicating change of speed, said instrument being rovided with a face plate, a body portion bac of said face plate and having inclined runways therein, said runways being/,inclined relative to said face plate in accordance with a predetermined scale, and a sphere in each of said runways.

12. A device`of the' class described comprising a face plate, a body portion back of said face plate, said body portion being provided with a plurality of inclined run- I ways, the inclination of said runways being graduatedv in accordance with a predetermined scale, spheres in each of said runways, a movable slide provided with openings adjacent the upper ends of said lrunways whereby spheresrpassing'upwardly in said runways drop into said openings, and

means to raise said slide whereby the bottom portion of said openings return said spheres to their respective runways. 'y

13. A device of the class described comies 

